What Is OI Confirmation?

A large options trade only tells you a trade happened. OI confirmation tells you whether it actually created a new position.

OI confirmation is the practice of checking a strike's open interest (OI) after a large or unusual trade to see whether OI actually rose. If it did, the trade likely opened fresh contracts — a genuinely new position. If OI stayed flat or fell instead, the trade was more likely closing out an existing position, which is a very different situation even though the trade itself looked identical on the tape.

Why the same-looking trade can mean opposite things

Picture two trades that look identical: both are a 1,000-lot buy on the same strike, at the same price, at the same time. One of them is a trader opening a brand-new bullish position. The other is a trader who was short that option closing out — buying back a position they'd previously sold. From the trade print alone, there is no way to tell these apart. The only way to tell is to check what happened to open interest afterward.

Why this matters for interpreting flow

A trade that opens a brand-new position is a much stronger signal of a fresh view than a trade that merely closes out an old one. Without checking OI, both would look identical on a plain flow feed — a large trade is a large trade. OI confirmation is the extra step that separates "someone is building a new position" from "someone is just closing an old one out," which materially changes how much weight the trade deserves.

A practical complication

Open interest for NSE F&O contracts isn't published tick-by-tick the way trades are — it's reported periodically through the day, so there's naturally a short lag between a trade happening and OI reflecting it. Any OI-confirmation check has to account for that lag, or it risks grading a trade on stale data.